Speaking of solar (see below), the growing interest in photovoltaics has sparked a sharp increase in the price of the high-quality silicon needed to make standard solar panels. It turns out that most silicon has too many other metals intermixed in the ore to be usable for photovoltaic power; processes for removing the contaminants exist, but are far too expensive to be worthwhile, even at current high silicon prices. But @Monkeysign points us to new research by a team in Berkeley which may make it far easier -- and cheaper -- to turn "dirty" silicon into pv-grade material.